File extensions – definition and basic information


File extensions are the integral parts of the files that are on each computer. Often, when working on a computer, we encounter a wide range of files, such as docx, ppt, part, mp3 or rmvb. We realize that they are there – but we often do not know what they are for on our computer.

File extension, also known as the filename extension is a suffix added to the name of a computer file, usually consisting of a number of characters placed after the last dot in the filename, which gives us information about its coding. In other words a file extension is a file format. It allows the operating system (e.g. Windows) to recognize what program it should try to open the file.

In the table below you will find a random selection of popular file extensions.


File extension The full name of the file Category

AZW file extension

Amazon Kindle eBook File

eBook Files

SWF file extension

Shockwave Flash Movie

Video Files

PPS file extension

PowerPoint Slide Show

Data Files

VCD file extension

Virtual CD

Disk Image Files

APK file extension

Android Package File

Executable Files

KEYCHAIN file extension

Mac OS X Keychain File

Data Files

DEM file extension

Video Game Demo File

Game Files

7Z file extension

7-Zip Compressed File

Compressed Files

UUE file extension

Uuencoded File

Encoded Files

XHTML file extension

Extensible Hypertext Markup Language File

Web Files

ISO file extension

Disc Image File

Disk Image Files

DMP file extension

Windows Memory Dump

System Files

XML file extension

XML File

Data Files

KMZ file extension

Google Earth Placemark File

GIS Files

RAR file extension

WinRAR Compressed Archive

Compressed Files